The goal of this project is to develop a discrete event simulation model of pediatric asthma and to use this model to evaluate the impacts of interventions in the residential indoor environment on environmental exposures and asthma exacerbations. In spite of the significant public health burden of pediatric asthma, studies have not used discrete event simulation models or related systems science tools to model this disease or consider the efficacy of various interventions. Given the multi-factorial nature of asthma, it is particularly well-suited for discrete event simulation, which can track individuals over time and take account of multiple risk factors simultaneously. Interventions addressing ventilation in homes have the potential to improve respiratory health, given their effect on pollutants such as environmental tobacco smoke, nitrogen dioxide, and indoor allergens, but such interventions often display policy-resistant tendencies. Reduced ventilation will tend to increase the influence of indoor pollutant sources at the same time that it decreases the influence of outdoor pollutant sources. Ventilation changes can also influence indoor temperature and humidity, altering conditions for mold, dust mites, and other allergens, and residents may respond to changes in indoor conditions in ways that would offset the anticipated benefits of the interventions. The primary aims of this project include: 1) Develop a discrete event simulation model of pediatric asthma, simulating asthma exacerbations and related health care utilization based on lung function measures and other factors common in low-income urban settings that can influence the course of the disease, including health care status and medication adequacy;2) Model the relationship among key indoor environmental risk factors for asthma exacerbation and measures of lung function or other outcomes used in the discrete event simulation model of pediatric asthma;3) Model the effects of ventilation-related indoor environmental interventions on indoor air quality in multi-family housing, leveraging the results from detailed indoor air simulation models;and 4) Quantify the benefits and costs associated with various indoor environmental interventions to determine optimal strategies for reducing the burden of pediatric asthma. This project will provide insight about the benefits and tradeoffs associated with interventions in the residential indoor environment, and will provide a model framework that can be used to evaluate numerous interventions addressing pediatric asthma. PUBLIC HEALTH RELEVANCE: This project will provide insight about optimal strategies for reducing the public health burden of pediatric asthma through indoor environmental interventions. Many low- income urban asthmatics live in multi-family housing that may be amenable to ventilation-related interventions, but such interventions must be designed carefully given their offsetting effects on indoor and outdoor pollutants. The model developed in this project will help determine health-optimal strategies as existing buildings are retrofitted or new buildings are constructed, and can be used to consider a variety of environmental and non-environmental interventions targeting pediatric asthma.